You will only be able to exploit dynamic masking fully when you have become familiar with the principle behind it. Although masking itself may appear simple at first sight, very complex results can be achieved with its aid.
Dynamic masking extends the Calamus system not just by a single function – rather it strengthens all the design possibilities already present.
A mask group consists of a frame to be masked (called the
background frame
below) and one or more masking frames(!) The
masking frames in combination form the mask.
In the places where the mask is black, the objects of the background frame will be displayed in the usual manner. Where the mask is white or empty, the background object is hidden.
Where the background frame itself is already transparent, it will of course stay that way within the mask. The writing mode of the mask group affects only the current mask. Outside the mask the frame is always transparent!
As the dynamic masking takes place during output, the display of a masked object takes a little longer than for an unmasked object.
With dynamic masking the mask is evaluated anew each time it is output. Therefore the edges of a vectorially created mask will always be sharp, also (and particularly) during imagesetting.
If you mask a bitmap picture, then even the individual pixels of this image will be cut cleanly by the edge of the mask.
The same applies, of course, to the dots of a set raster. These too will be cut cleanly by the mask. Here the raster will continue without a break over the mask edge.
If you use a bitmap image as a mask then the edge of the mask will be jagged (rough) along the pixel edges, of course. The lower the resolution of the masking image, the rougher the outline. If you want smooth edges you can vectorize the masking image with the Speed~Line module, for instance, and use the vectorial version as a mask.
Everything has its limits. With masking they lie exactly there – in the limits or boundaries.
A mask is at present always only black or white and with that the subject is always opaque or transparent. You cannot achieve semi-transparency with a mask.
The boundary between a masked object and the background is always sharp, therefore. There are no soft transitions.
Semi-transparency and soft transitions can be achieved with the optional Merge module.
It is very important that you are clear about the fact that the mask is always evaluated as if it were on a monochrome screen. But that also means that it is (usually) not sensible to have any objects in the mask that are grey or coloured. In particular, it is not possible to achieve real semi-transparency in this way.
This is because coloured or grey areas too will be used in the same way as on a monochrome screen. This results in a colour being first converted to a corresponding grey value, and then rasterized. The small raster dots in the mask then only make tiny bits of the masked object visible. The same effect appears with fill patterns in masking objects.
Of course, nothing prevents you from using this mechanism as a design effect. And sometimes the result doesn't look too bad ...
Quite simply: Anything that you can also use in the document otherwise! A text frame that lies within an active piping chain, a group of objects of any desired complexity, an already separated fine-data image from an image processing program or even another mask group – no problem.
If you want to apply the same mask to more than one object, you must first form a (normal) group and then mask this group. Otherwise all but the rear-most frame would be incorporated in the mask.
If you don't want to experiment with spectacular, rastered masks, you should always build your masks only from black and white objects.
The masking process doesn't care in the least where these objects come from. You can also combine any number of different object types in one and the same mask, exactly as you can in the document layout.
Even already masked objects are permitted in a mask!
When forming the mask group, all elements of the mask remain completely unaltered. All operations such as mirroring, rotation, the writing mode or rasterizing settings and image control curves are also active within the mask.
An object with inverting writing mode will for instance alter the objects lying behind them in the mask in the same way as in the document layout.
In the same way you can punch a hole
in the mask by placing
a white, opaque shape on a black raster area. The mask will become
white in this position, in other words the mask group will be
transparent there.
By overlapping several black objects on the other hand you can
piece together
masks of any desired shape.
Experience shows that you can save yourself a lot of work if you put some thought into the structure of a complex mask beforehand. But even if things go wrong at times – you can always split up a mask group and correct the individual parts.
With a mask group you can only alter the general frame settings. Besides size and position changes this includes rotation, mirroring and the write mode.
These settings affect all frames within a mask group and remain in place even when the group is split up.
The only exception: The write mode only affects the frame being masked, not the frames forming the mask:
This is one of the most interesting advantages of dynamic
masking. As the mask groups are fully integrated into the Calamus
document structure, it is possible to go into
the closed group
to some extent and edit the individual components!
For you the process is very simple: Make a virtual copy of the mask group and split it up. The individual parts of the copy remain connected with the corresonding parts of the original.
Any change to the contents of the virtual copies will then be reflected in the mask group as well, no matter whether you import images, edit text or correct vector paths.
With the Toolbox module you can go a step further: Create the
virtual copy exactly on top of the original and split up the mask
group as described above. So that the individual parts of the copy do
not cover the original, make them invisible with the toolbox! Make
sure that you have activated the Edit invisible frame
option in
the Frame editor parameters function group of the Frame editing
module.
Now you can select the individual frames and alter their contents.
(You may have to click through
to the correct frame). As the
mask group will be changed immediately as well, you can observe the
effect directly.
In particular where text is concerned, there are often last-minute changes. With this procedure you will have no problems with this.
Tip: As virtual copies of objects occupy very little
memory, you can keep the working copies
until the document is
output. If you have invisible objects in your document, Calamus will
ask during printing whether these invisible frames should be printed
as well. You should reply to the query with No
.
Tip: When you use a vector graphics frame as a mask, you can also change the positions of the individual mask portions relative to each other, as the position of objects within the same vector graphic is included in the contents!
